Recently, image capturing apparatuses (cameras) such as a video camera and digital still camera using solid-state image sensors require a compact, wide-angle zoom lens.
As a compact, wide-angle zoom lens, there is known a negative lead type zoom lens which has a lens unit of negative refractive power on the most object side and is formed from a plurality of lens units as a whole.
A known example of the negative lead type zoom lens is a 2-unit zoom lens which includes, sequentially from the object side to the image side, a first lens unit L1 of negative refractive power and a second lens unit L2 of positive refractive power, and performs zooming by moving the respective lens units (Japanese Patent Laid-Open No. 05-249374).
Another example is a 3-unit zoom lens which includes, sequentially from the object side to the image side, a first lens unit of negative refractive power, a second lens unit of positive refractive power, and a third lens unit of positive refractive power, performs zooming by moving the respective lens units, and has good telecentricity on the image side (Japanese Patent Laid-Open Nos. 2001-66503 and 2001-281545).
Japanese Patent Laid-Open Nos. 2001-66503 and 2001-281545 each disclose a compact zoom lens having a first lens unit made up of negative and positive lenses.
Generally in the negative lead type zoom lens, a larger angle of view increases negative distortion aberration on the wide-angle end. Optically correcting the negative distortion aberration requires many lenses, and it is very difficult to sufficiently correct such aberration.
For this reason, there has conventionally been known a zoom lens which corrects negative distortion aberration not optically but electrically (Japanese Patent Laid-Open Nos. 2006-47537, 2006-284790, 2006-330675, and 2-252375).
A known example of the zoom lens which electrically corrects negative distortion aberration is one which makes correction only in the zoom range where negative distortion aberration becomes large (Japanese Patent Laid-Open No. 6-181530).
The negative lead type zoom lens in which a lens unit of negative refractive power precedes has a feature capable of easily achieving downsizing and a wide angle of view.
However, the entire zoom lens is asymmetric, so distortion aberration readily occurs on the wide-angle end.
The negative distortion aberration becomes large as the angle of view of the zoom lens increases.
Various methods of electrically correcting negative distortion aberration have been proposed.
However, even by the method of simply making electrical correction of distortion aberration, it is difficult to sufficiently correct distortion aberration on the entire plane and maintain high optical performance while decreasing the front lens diameter and downsizing the zoom lens.
When electrically correcting distortion aberration, consideration should be made regarding the generation state (generation amount) of distortion aberration in each zoom range of the zoom lens, the lens arrangement, and the like; otherwise, it is very difficult to satisfactorily correct distortion aberration in all zoom ranges and obtain high optical performance (high-quality image) while decreasing the front lens diameter and downsizing the zoom lens.